Empirical specification requirements for two-constant models of recreationchoice

Two-constraint models art common in recreation-demand analysis because of t he important role time can pla!: in consumer choices. Two versions of Rev's identity hold for these models and imply coefficient restrictions on empir ical demand functions. The two-constraint restrictions ale fully observable and can be expressed in a form analogous to the Slutsky-Hicks equations in single constraint consumer models. Empirical specifications that use full prices and full budgets can be consistent with the two-constraint models, w hen the marginal value of time is either exogenous or endogenous. but model s with full prices and money income alone art: not.